Glucose-Restricted Diet Regulates the Tumor Immune Microenvironment and Prevents Tumor Growth in Lung Adenocarcinoma

Short-chain fatty acids induced lung tumor cell death and increased peripheral blood CD4+ T cells in NSCLC and control patients ex vivo

Background

Despite therapy advances, one of the leading causes of cancer deaths still remains lung cancer. To improve current treatments or prevent non-small cell lung cancer (NSCLC), the role of the nutrition in cancer onset and progression needs to be understood in more detail. While in colorectal cancer, the influence of local microbiota derived SCFAs have been well investigated, the influence of SCFA on lung cancer cells via peripheral blood immune system should be investigated more deeply. In this respect, nutrients absorbed via the gut might affect the tumor microenvironment (TME) and thus play an important role in tumor cell growth.

Objective

This study focuses on the impact of the short-chain fatty acid (SCFA) Sodium Butyrate (SB), on lung cancer cell survival. We previously described a pro-tumoral role of glucose on A549 lung adenocarcinoma cell line. In this study, we wanted to know if SB would counteract the effect of glucose and thus cultured A549 and H520 in vitro with and without SB in the presence or absence of glucose and investigated how the treatment with SB affects the survival of lung cancer cells and its influence on immune cells fighting against lung cancer.

Methods

In this study, we performed cell culture experiments with A549, H520 and NSCLC-patient-derived epithelial cells under different SB levels. To investigate the influence on the immune system, we performed in vitro culture of peripheral mononuclear blood cells (PBMC) from control, smoker and lung cancer patients with increasing SB concentrations.

Results

To investigate the effect of SB on lung tumor cells, we first analyzed the effect of 6 different concentrations of SB on A549 cells at 48 and 72 hours cell culture. Here we found that, SB treatment reduced lung cancer cell survival in a concentration dependent manner. We next focused our deeper analysis on the two concentrations, which caused the maximal reduction in cell survival. Here, we observed that SB led to cell cycle arrest and induced early apoptosis in A549 lung cancer cells. The expression of cell cycle regulatory proteins and A549 lung cancer stem cell markers (CD90) was induced. Additionally, this study explored the role of interferon-gamma (IFN-γ) and its receptor (IFN-γ-R1) in combination with SB treatment, revealing that, although IFN-γ-R1 expression was increased, IFN-γ did not affect the efficacy of SB in reducing tumor cell viability. Furthermore, we examined the effects of SB on immune cells, specifically CD8+ T cells and natural killer (NK) cells from healthy individuals, smokers, and NSCLC patients. SB treatment resulted in a decreased production of IFN-γ and granzyme B in CD8+ T cells and NK cells. Moreover, SB induced IFN-γ-R1 in NK cells and CD4+ T cells in the absence of glucose both in PBMCs from controls and NSCLC subjects.

Conclusion

Overall, this study highlights the potential of SB in inhibiting lung cancer cell growth, triggering apoptosis, inducing cell cycle arrest, and modulating immune responses by activating peripheral blood CD4+ T cells while selectively inducing IFN-γ-R1 in NK cells in peripheral blood and inhibiting peripheral blood CD8+ T cells and NK cells. Thus, understanding the mechanisms of action of SB in the TME and its influence on the immune system provide valuable insights of potentially considering SB as a candidate for adjunctive therapies in NSCLC.

Gut microbiota and dietary intervention: affecting immunotherapy efficacy in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) accounts for 80-85% of all lung cancers. In recent years, treatment with immune checkpoint inhibitors (ICIs) has gradually improved the survival rate of patients with NSCLC, especially those in the advanced stages. ICIs can block the tolerance pathways that are overexpressed by tumor cells and maintain the protective activity of immune system components against cancer cells. Emerging clinical evidence suggests that gut microbiota may modulate responses to ICIs treatment, possibly holding a key role in tumor immune surveillance and the efficacy of ICIs. Studies have also shown that diet can influence the abundance of gut microbiota in humans, therefore, dietary interventions and the adjustment of the gut microbiota is a novel and promising treatment strategy for adjunctive cancer therapy. This review comprehensively summarizes the effects of gut microbiota, antibiotics (ATBs), and dietary intervention on the efficacy of immunotherapy in NSCLC, with the aim of informing the development of novel strategies in NSCLC immunotherapy.

Exploring the interplay between methylation patterns and non-coding RNAs in non-small cell lung cancer: Implications for pathogenesis and therapeutic targets

Lung cancer is a global public health issue, with non-small cell lung cancer (NSCLC) accounting for 80-85 % of cases. With over two million new diagnoses annually, understanding the complex evolution of this disease is crucial. The development of lung cancer involves a complex interplay of genetic, epigenetic, and environmental factors, leading the key oncogenes and tumor suppressor genes to disorder, and activating the cancer related signaling pathway. Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNA (lncRNAs), and circular RNA (circRNAs) are unique RNA transcripts with diverse biological functions. These ncRNAs are generated through genome transcription and play essential roles in cellular processes. Epigenetic modifications such as DNA methylation, N6-methyladenosine (m6A) modification, and histone methylation have gained significant attention in NSCLC research. The complexity of the interactions among these methylation modifications and ncRNAs contribute to the precise regulation of NSCLC development. This review comprehensively summarizes the associations between ncRNAs and different methylation modifications and discusses their effects on NSCLC. By elucidating these relationships, we aim to advance our understanding of NSCLC pathogenesis and identify potential therapeutic targets for this devastating disease.

ROS regulation in gliomas: implications for treatment strategies

Gliomas are one of the most common primary malignant tumours of the central nervous system (CNS), of which glioblastomas (GBMs) are the most common and destructive type. The glioma tumour microenvironment (TME) has unique characteristics, such as hypoxia, the blood-brain barrier (BBB), reactive oxygen species (ROS) and tumour neovascularization. Therefore, the traditional treatment effect is limited. As cellular oxidative metabolites, ROS not only promote the occurrence and development of gliomas but also affect immune cells in the immune microenvironment. In contrast, either too high or too low ROS levels are detrimental to the survival of glioma cells, which indicates the threshold of ROS. Therefore, an in-depth understanding of the mechanisms of ROS production and scavenging, the threshold of ROS, and the role of ROS in the glioma TME can provide new methods and strategies for glioma treatment. Current methods to increase ROS include photodynamic therapy (PDT), sonodynamic therapy (SDT), and chemodynamic therapy (CDT), etc., and methods to eliminate ROS include the ingestion of antioxidants. Increasing/scavenging ROS is potentially applicable treatment, and further studies will help to provide more effective strategies for glioma treatment.

Consuming intracellular glucose and regulating the levels of O2/H2O2 via the closed cascade catalysis system of Cu-CeO2 nanozyme and glucose oxidase

Imbalances in the intracellular environment caused by high levels of glucose, H2O2, and hypoxia can greatly impact cancer development and treatment. However, there is limited research on regulating the levels of these species simultaneously in tumor cells. Here, a pH-responsive nanozyme-enzyme hybrid system was developed to regulate intracellular glucose, H2O2 and O2. The system, named DMSN@Cu-CeO2@GOx, consists of Cu-CeO2 nanoparticles and glucose oxidase (GOx) immobilized in dendritic mesoporous silica (DMSN) spheres. GOx efficiently consumes glucose in tumor cells, causing a drop in pH and producing a significant amount of H2O2. Cu-CeO2 then catalyzes the conversion of H2O2 to O2 due to its high catalase-like (CAT) activity in weakly acidic conditions. The process was monitored by fluorescence probes, and the mechanism was investigated through fluorescence spectroscopy and confocal laser scanning microscopy. The cascade catalytic system with excellent biocompatibility continuously consumes glucose and elevates the level of O2 in cells. This hybrid nanomaterial offers a means to regulate the glucose/H2O2/O2 levels in cells and may provide insights into starvation therapy by modulating reactive species within cells.

Cancer Cell-Intrinsic Alterations Associated with an Immunosuppressive Tumor Microenvironment and Resistance to Immunotherapy in Lung Cancer

Despite the great clinical success of immunotherapy in lung cancer patients, only a small percentage of them (<40%) will benefit from this therapy alone or combined with other strategies. Cancer cell-intrinsic and cell-extrinsic mechanisms have been associated with a lack of response to immunotherapy. The present study is focused on cancer cell-intrinsic genetic, epigenetic, transcriptomic and metabolic alterations that reshape the tumor microenvironment (TME) and determine response or refractoriness to immune checkpoint inhibitors (ICIs). Mutations in KRAS, SKT11(LKB1), KEAP1 and TP53 and co-mutations of these genes are the main determinants of ICI response in non-small-cell lung cancer (NSCLC) patients. Recent insights into metabolic changes in cancer cells that impose restrictions on cytotoxic T cells and the efficacy of ICIs indicate that targeting such metabolic restrictions may favor therapeutic responses. Other emerging pathways for therapeutic interventions include epigenetic modulators and DNA damage repair (DDR) pathways, especially in small-cell lung cancer (SCLC). Therefore, the many potential pathways for enhancing the effect of ICIs suggest that, in a few years, we will have much more personalized medicine for lung cancer patients treated with immunotherapy. Such strategies could include vaccines and chimeric antigen receptor (CAR) cells.

Contribution of serum lipids and cholesterol cellular metabolism in lung cancer development and progression

Neoplasms of the lungs are the leading cause of cancer incidence and mortality worldwide. Although immunotherapy has increased the overall survival of patients with lung cancer, there is the need to improve this treatment. At this regard, blood lipid levels are thought to be linked to cancer risk and thus a preventive intervention through regulation of the nutrition of patients with lung cancer is gaining much attention. In this study, we therefore asked about the contribution of serum lipids and cholesterol cellular metabolism in lung cancer development and progression. We measured different serum lipids and analyzed cholesterol synthesis enzymes 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGCR) and acetyl-coenzyme A cholesterol acetyltransferase 1 (ACAT1) as well as the cholesterol cellular export protein ATP-binding cassette (ABC) A-1 mRNA by quantitative PCR (qPCR) in the control and tumoral regions of post-surgery lung tissues to analyze the accumulation of cholesterol in cancer cells in a cohort of patients with lung adenocarcinoma (LUAD). We found that triglycerides in serum directly correlated with the body mass index (BMI) in patients with LUAD. By contrast, we found that high-density lipoprotein (HDL) cholesterol inversely correlated with the BMI, C-reactive protein (CRP) and overall survival and total cholesterol inversely correlated with the tumor diameter, serum CRP and overall survival in these LUAD patients. Functionally, the role of cholesterol is indispensable for the growth and development of normal animal cells where it is tightly regulated. Excess of cellular cholesterol regulated by HMGCR is converted to cholesteryl esters by the enzyme ACAT1 and exported extracellularly by the cholesterol transporter ABCA1. Here we found HMGCR and ACAT1 upregulated and ABCA1 downregulated in the lung's tumoral region of our LUAD cohort, indicating cholesterol dysregulated cellular export in lung tumor cells.